Novak Djokovic and I are discussing dinosaurs. It's a Sunday afternoon in early August, and we're talking about velociraptors and sauropods in a darkened room underneath the Aviva Centre, on the outskirts of Toronto. Djokovic is in Canada for his first tournament since winning Wimbledon three weeks earlier, a victory that snapped a bizarre two-year slump. Virtually overnight, he went from being arguably the most dominant player the men's game had ever seen to a guy on the verge of, well, extinction.

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Djokovic tells me that his 3-year-old son, Stefan, who commandeered the spotlight during the Wimbledon trophy ceremony with his beaming smile and exuberant clapping, is obsessed with dinosaurs. Which is why when his family -- in addition to Stefan, there's his wife, Jelena, and the couple's 11-month-old daughter, Tara -- joins him in New York in a few weeks for the US Open, dinosaur tourism will be atop the agenda. I mention that I've spent many hours in the American Museum of Natural History with my kids, and Djokovic leans forward. "I've heard that they have, like, sleepovers and stuff?" It is unclear to me whether he is inquiring for Stefan or for himself. A moment later, he says, "I'll have to try to get a dinosaur outfit."

Stefan likes tennis too, his father says, though he wants to hit only forehands. Given that Djokovic has possibly the finest two-handed backhand of all time, this could be interpreted as a sign of rebelliousness. But Djokovic claims he isn't worried: "I know he'll have a good backhand; it's in his DNA."

Djokovic had arrived in Toronto the day before from a family vacation in Spain. And even now, he's dressed like it's cocktail hour back in Marbella: a white polo shirt, olive-green khaki trousers and casual white sneakers with thin black socks visible just below the cuffs. Djokovic is in a relaxed, expansive mood, but there's also a palpable sense of relief in his voice -- a feeling that comes from being able to talk about his slump in the past tense. In fact, "relief" is the first word he uses to describe what he felt upon defeating No. 8-ranked Kevin Anderson to win his fourth Wimbledon crown last month.

When I ask him what everyone wants to know (What the hell happened?), the 31-year-old Serb flashes a wry smile. "I lost my mojo," he answers. After winning the French Open in 2016, finally claiming the one major that had eluded him, he had no fight left. "I couldn't hear the score" is how he puts it. He tried to play through this malaise and ended up with an elbow injury that sidelined him for the second half of the 2017 season. "My emotional tank for competing was empty," he says. It was a disorienting experience, the athlete's equivalent of writer's block, and a frightening one, because he had no way of knowing if he could recover the edge he'd lost. "I was questioning whether I could get back to the level I had played for so many years," he says.

Lots of other people were too. But the Wimbledon run in July, which included a five-set, five-hour semifinal win over Rafael Nadal, ended his slide in the most emphatic way possible. With his punishing down-the-line backhands and contortionist retrieving, he looked like the Djokovic of old. But much has changed for him in the past two years. For starters, he's using a longer, lighter version of his racket. He also switched clothing and shoe sponsors, from Uniqlo and Adidas to Lacoste and Asics. But the biggest difference is in Djokovic himself. "I'm a different person in many ways," he says. "First of all, I'm a father of two kids. I still play tennis, which I truly love with all my heart and I'm grateful that I have an opportunity to compete at a high level. But I just see myself differently. My biggest interest is to keep on exploring the possibilities of my existence on this planet -- not just as a tennis player but as a human being.

"It's not only about winning a tennis match," he says. "You can't take trophies to your grave."

For two years, Djokovic was the most dominant player in men's tennis, claiming four consecutive majors and notching a 92 percent win percentage. John Minchillo/AP Photo

Djokovic's downward spiral was astonishing not just because of its severity but because of how abruptly it happened. Between July 2014, when he claimed his second Wimbledon title, and June 2016, when he hoisted the French Open trophy for the first time, Djokovic won 158 matches against just 13 losses, a 92 percent win rate. In that time, he won six majors, four consecutively -- the so-called Nole Slam. (Nole is one of Djokovic's nicknames.) Neither Nadal nor Roger Federer has ever won four in a row. Andre Agassi, who briefly coached Djokovic during his slump, said the Serb took tennis to another dimension during that epic run. "There was no standard of tennis ever higher than that," Agassi says, though he cautioned that he was not wading into the GOAT debate. "Nobody has played at that level."

When he captured the French in 2016, it seemed no longer a question of whether Djokovic would overtake Federer's record for majors -- he had 17 at the time -- but how quickly he would do it.

Then the winning suddenly stopped. A month after his victory in Paris, he lost in the third round at Wimbledon to 28th-seeded American Sam Querrey, one of the biggest upsets in tournament history. Five weeks later, Juan Martin del Potro eliminated him from the first round of the Rio Olympics, and Djokovic left the court in tears. "The heartbreaking loss in the Olympic Games, that hurt me a lot and that's probably where I spent everything that was left in the tank," he says.

He rallied enough to make the final at the US Open, where he was heavily favored. But Stan Wawrinka pushed him around the court, hitting one ground stroke so hard it knocked the racket out of Djokovic's hand. Most striking was how meekly Djokovic went down in the fourth set; he looked lost and defeated. It was a sign of things to come. Over the next 23 months, Djokovic would win just two tournaments and wouldn't make it past the quarterfinals of a major.

Djokovic's wife, Jelena, and 3-year-old son, Stefan, cheer him on against Kevin Anderson at the Wimbledon final. Ben Curtis/AP Photo

In Toronto, Djokovic tells me that when the Wawrinka match went to the fourth set, the urgency and intensity that he had always been able to summon wasn't there. "I felt like, 'Wow, I have to go through this again?'"

"I hit a wall, emotionally," he says. "As much as I was fulfilled with holding four slams at the time and being No. 1 and at the pinnacle of my career, I was drained."

He tried to play his way out of it. "I assure you I was practicing even harder than normal," he says, but that was a mistake. "There was a battle inside of me. The old me was used to pushing through, forgetting about everything. As a professional athlete, you need that character strength, that resilience. But at the same time, there was something happening that needed to be addressed that didn't get addressed the right way." In hindsight, he says, he should have ended his 2016 season after the loss against Wawrinka.

Tennis Channel commentator Mary Carillo believes that, paradoxical as it might sound, it was Djokovic's victory at the French, his ultimate conquest, that sent him into a downward spiral. Winning in Paris wasn't just about filling in the missing line on his résumé; the dying wish of his childhood coach, Jelena Gencic, had been for him to triumph at Roland Garros. "When he was finally able to capture the French Open," Carillo says, "it meant he had fulfilled his destiny. At a certain point you look around and you say, 'All right, I have just done everything I have ever dreamed of doing.' And he must have felt exhaustion, relief."

As his on-court performances slipped, his life off the court came under scrutiny. There were rumors of marital discord, fueled in part by his admission after the Querrey loss that "personal issues" had been weighing on him. It didn't help when BBC and ESPN analyst John McEnroe suggested on air during Wimbledon last year that Djokovic was similar to Tiger Woods.

Also a source of intrigue was Djokovic's relationship with Pepe Imaz, a coach and spiritual adviser who runs an academy in Marbella called the Love and Peace Tennis School. Imaz, who believes in telekinesis and telepathy and whose training methods include long group hugs, was in Djokovic's box during the 2016 US Open. Adding to suspicion that Imaz was exercising undue influence was the sudden upheaval in Djokovic's camp. He ran through a series of coaches, including Boris Becker, who had helped coach him to six majors, his longtime coach Marian Vajda and Agassi.

Djokovic seemed unmoored. After taking off the second half of the 2017 season, he finally decided to have surgery on his elbow in February. Barely a month later, he was back on the court at Indian Wells but lasted just one match there, losing to qualifier Taro Daniel. As a gaunt-looking Djokovic unraveled in the third set, a funereal hush settled over the media center. Daniel was as stunned as everyone else, telling reporters: "The Djokovic I know is like the Djokovic I see on TV, and he never misses a ball. Today, obviously, he was missing a lot of balls."

Djokovic's struggles continued in Miami two weeks later, when he lost his first match to 47th-ranked Frenchman Benoit Paire. "Miami especially was very frustrating because I haven't felt that way, I think, ever since I started my professional career," Djokovic says. "I just felt helpless."

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"Helpless" is hardly a word anyone would use to describe the Novak Djokovic of late.

A week before the US Open, on a miraculously rain-free afternoon at the Western & Southern Open in Cincinnati, Djokovic found himself facing off against Federer in the final. Again. He'd notched five runner-up performances there, three of them to Federer. But this time, Djokovic was unstoppable. Using a lethal mix of depth and angles to keep his old rival constantly off balance, he logged a nearly flawless performance, beating Federer in straight sets for his first Cincinnati title.

"It came at the right time against the player who is probably regarded as the greatest ever to hold a tennis racket," he told me just after the match. "Playing the final five times and failing to overcome the last hurdle -- that's what makes this success even more special."

It also proved that Wimbledon had been no fluke; five months after staggering off the court in Indian Wells, Novak Djokovic enters the US Open as the man to beat. He will face 40th-ranked Hungarian Marton Fucsovics in the first round on Tuesday.

Djokovic celebrates defeating Roger Federer to win the Western & Southern Open in Cincinnati, the last tournament before the US Open. John Minchillo/AP Photo

Plenty of things have been credited for his return to top form. For one, his elbow healed. As Federer himself noted in a news conference in New York on Friday, the injury had been hindering Djokovic's game earlier in the season. "With Novak, it's been more the arm," Federer said. "When he came back, he wasn't quite ready yet. His serve wasn't really working, he wasn't hitting his spots. [But] he's shown how great he is by winning Wimbledon." Djokovic also reunited with Vajda, who has coached him since he was a teen and who has been at his side for all 13 of his grand slam wins. But Djokovic says he didn't change his training or his strategy. "It was honestly just a question of playing matches and being patient," he says.

Gordon Uehling, a close friend of Djokovic's who spoke regularly with him as he weathered the slump, says that while Djokovic was frustrated by his poor results on the court, he was not in a dark place mentally. "The thing that I found really interesting is that he wasn't so down," Uehling says. "He was pretty upbeat. He had a new child. He was living life in a different way. There wasn't a depressive way about him."

Family and fatherhood gave Djokovic a new sense of perspective, one that he maintained even during the worst moments. "When I was not doing well in tennis, part of me didn't like that, but I was still very happy because I had many things in my life that were making me fulfilled," he says.

"There is so much that we can learn from children, it's quite incredible. My wife and I, we call both our children our little masters. Because they are just able to be so present and fully engaged in the moment, and then they are able to move on from something that has happened."

As gratified as he is to be winning again, Djokovic says that victory doesn't make leaving them behind any easier. "It was really hard for me now to separate from them, I must admit," he says of leaving his family vacation in Spain to fly to Toronto. "When I left, it was very early in the morning and they were all sleeping -- so I left a note to my wife and to my kids on the table next to the bed [telling them] just how much I missed them and how much I loved them. But at the same time, I have their full support."

Whatever issues there might have been in his marriage, Djokovic spoke glowingly of his wife. He credited her with being instrumental in helping him regain his drive. "She likes to go in depth and analyze everything in detail," he says. "She likes to write in her journals and makes me do the same. We had many profound conversations that revealed a lot to both of us, and about me specifically. She helped me to identify the emotions and feelings of everything that is going on and understand the big picture."

"It's not only about winning a tennis match," Djokovic says. "You can't take trophies to your grave." Markian Lozowchuk/Redux for ESPN

Part of that big picture, he says, is thinking more about how he can use his platform as an elite athlete to advocate for social change. He doesn't have to look far for a role model. "[Serena Williams] is a great inspiration, to come back, play finals at Wimbledon shortly after giving birth. ... She keeps talking about it, and she should," he says. For his part, he wants to fight for health and early childhood education. The latter is the focus of his Belgrade-based foundation. "I don't think the world pays too much attention to early childhood development, and those are the crucial years when the human brain is developing the fastest," he says. "It's one of the crucial problems we have in Serbia. Over 50 percent of children do not attend preschool institutions."

Serena is also his inspiration when it comes to balancing work and family. "[She] inspires other athletes that it's possible to do both. ... Actually we were texting and speaking just before she went into labor, and she was so friendly and so kind and so loving to share what she's going through with us. And I felt that we connected on a deeper level."

That deeper level of meaning off the court is what seems to be fueling Djokovic's renewed drive on it. For years, no one in pro tennis lived a more ascetic life. His training regimen was notoriously fanatical -- hours of stretching each day, a hyperbaric chamber to aid recovery. His diet was spartan, designed only to enhance performance, with no allowance for pleasure except for the square of chocolate (yes, one square) that he would permit himself after big wins. But now he appears to be letting loose -- if only a bit. At the very least, he's striving for balance. As we walk toward the locker room in Toronto, I ask Djokovic if he eats ice cream with Stefan. He chuckles. "Yeah, we all eat the ice cream. Healthy ice cream."